Battery pack

ABSTRACT

Disclosed is a battery pack, which includes at least one battery module and a pack case for packaging the at least one battery module, and the battery pack includes a case base configured to support the at least one battery module, a case body coupled to the case base to accommodate the at least one battery module, and a case cover coupled to the case body to cover the case body, wherein the case base and the case body are sealed to each other and the case body and the case cover are sealed to each other, respectively, by means of a sealant member along a rim thereof.

TECHNICAL FIELD

The present disclosure relates to a battery pack.

The present application claims priority to Korean Patent Application No.10-2016-0143387 filed on Oct. 31, 2016 in the Republic of Korea, thedisclosures of which are incorporated herein by reference.

BACKGROUND ART

A secondary battery, which is easily applied to various product groupsand has electrical characteristics such as high energy density, isuniversally applied not only for a portable device but also for anelectric vehicle (EV), a hybrid electric vehicles (HEV) or the like,which is driven by an electric driving source. The secondary battery isattracting attention as a new environment-friendly energy source forimproving energy efficiency since it gives a primary advantage ofreducing the use of fossil fuels and also does not generate by-productsby the use of energy at all.

Secondary batteries widely used at the preset include lithium ionbatteries, lithium polymer batteries, nickel cadmium batteries, nickelhydrogen batteries, nickel zinc batteries and the like. An operatingvoltage of the unit secondary battery cell, namely a unit battery cell,is about 2.5V to 4.2V. Therefore, if a higher output voltage isrequired, a plurality of battery cells may be connected in series toconfigure a battery pack. In addition, depending on the charge/dischargecapacity required for the battery pack, a plurality of battery cells maybe connected in parallel to configure a battery pack. Thus, the numberof battery cells included in the battery pack may be variously setaccording to the required output voltage or the demandedcharge/discharge capacity.

Meanwhile, when a plurality of battery cells are connected in series orin parallel to configure a battery pack, it is common to configure abattery module composed of at least one battery cell first, and thenconfigure a battery pack by using at least one battery module and addingother components. Here, depending on various voltage and capacityrequirements, the battery pack including at least one battery module maybe used for a home, or battery racks including at least one battery packmay be combined to configure a power storage device for industrial use.

In the conventional battery pack, a waterproof and dustproof structurecapable of preventing foreign matter such as moisture and dust frompenetrating from the outside is particularly important due tocharacteristics of a battery, which is a secondary battery. Inparticular, when the battery pack is used as a home energy storagedevice, the waterproof and dustproof structure may become more importantfor the safety of a user or the like.

Therefore, there is a need to search for a method of providing a batterypack having a waterproof and dustproof structure with betterairtightness and efficiency.

DISCLOSURE Technical Problem

The present disclosure is directed to providing a battery pack having awaterproof and dustproof structure with better airtightness andefficiency.

Technical Solution

In one aspect of the present disclosure, there is provided a batterypack, which includes at least one battery module and a pack case forpackaging the at least one battery module, the battery pack comprising:a case base configured to support the at least one battery module; acase body coupled to the case base to accommodate the at least onebattery module; and a case cover coupled to the case body to cover thecase body, wherein the case base and the case body are sealed to eachother and the case body and the case cover are sealed to each other,respectively, by means of a sealant member along a rim thereof.

The case body may include: a first inner case configured to fix the atleast one battery module; an outer case configured to surround the firstinner case and form an accommodation space for accommodating the atleast one battery module; and a second inner case mounted to an upperside of the outer case and coupled to the case cover.

The second inner case may be mutually sealed to the outer case by meansof the sealant member.

The second inner case may be mutually sealed to the case cover by meansof the sealant member.

The outer case may be mutually sealed to the case base by means of thesealant member.

The case base may include a base mount mounted to the at least onebattery module; and drainage holes provided at both sides of the basemount and formed to have a step from the base mount.

An upper surface of the base mount may be inclined downwards toward thedrainage hole.

The battery pack may further comprise at least one mesh unit mounted tothe drainage hole.

The at least one mesh unit may include: a first mesh frame mounted to anupper side of the drainage hole; a first mesh net mounted to the firstmesh frame; a second mesh frame mounted to a lower side of the drainagehole; and a second mesh net mounted to the second mesh frame anddisposed opposite to the first mesh net.

The first mesh net and the second mesh net may be arranged with mutuallyalternating net structures.

The first mesh net and the second mesh net may be spaced apparat fromeach other by at least 2 mm.

The at least one mesh unit may include a dust-protecting filter providedbetween the first mesh net and the second mesh net.

The dust-protecting filter may have a volume corresponding to the spacebetween the first mesh net and the second mesh net.

The dust-protecting filter may filter off foreign matter including dustwith a size of 10 μm or above.

The battery pack may be a home energy storage device.

Advantageous Effects

According to various embodiments as above, it is possible to provide abattery pack having a waterproof and dustproof structure with betterairtightness and efficiency.

DESCRIPTION OF DRAWINGS

The accompanying drawings illustrate a preferred embodiment of thepresent disclosure and together with the foregoing disclosure, serve toprovide further understanding of the technical features of the presentdisclosure, and thus, the present disclosure is not construed as beinglimited to the drawing.

FIG. 1 is a diagram for illustrating a battery pack according to anembodiment of the present disclosure.

FIG. 2 is an exploded perspective view showing the battery pack of FIG.1.

FIG. 3 is a perspective view showing a case base of a pack case,employed at the battery pack of FIG. 2.

FIG. 4 is a diagram for illustrating a mesh unit mounted to the casebase of FIG. 3.

FIG. 5 is a cross-sectional view showing the case base of FIG. 3.

FIG. 6 is a sectional view showing a lower portion of the battery packof FIG. 1.

FIG. 7 is a front view showing the battery pack of FIG. 1.

FIG. 8 is a side view showing the battery pack of FIG. 1.

FIGS. 9 and 10 are diagrams for illustrating how to transport thebattery pack of FIG. 1.

FIGS. 11 to 13 are diagrams for illustrating how to mount a mountbracket of the battery pack of FIG. 1.

BEST MODE

The present disclosure will become more apparent by describing in detailthe embodiments of the present disclosure with reference to theaccompanying drawings. It should be understood that the embodimentsdisclosed herein are illustrative only for better understanding of thepresent disclosure, and that the present disclosure may be modified invarious ways. In addition, for ease understanding of the presentdisclosure, the accompanying drawings are not drawn to real scale, butthe dimensions of some components may be exaggerated.

FIG. 1 is a diagram for illustrating a battery pack according to anembodiment of the present disclosure, FIG. 2 is an exploded perspectiveview showing the battery pack of FIG. 1, FIG. 3 is a perspective viewshowing a case base of a pack case, employed at the battery pack of FIG.2, FIG. 4 is a diagram for illustrating a mesh unit mounted to the casebase of FIG. 3, FIG. 5 is a cross-sectional view showing the case baseof FIG. 3, FIG. 6 is a sectional view showing a lower portion of thebattery pack of FIG. 1, FIG. 7 is a front view showing the battery packof FIG. 1, and FIG. 8 is a side view showing the battery pack of FIG. 1.

Referring to FIGS. 1 to 8, a battery pack 10 is an energy source and maybe used as an industrial or home energy storage device. Also, thebattery pack 10 may be used as an energy source for a vehicle such as anelectric vehicle or a hybrid electric vehicle, which have recently beenattracting attention. Hereinafter, this embodiment will be describedbased on the case where the battery pack 10 is used as a home energystorage device.

The battery pack 10 may include a battery module 100, a pack case 200, aBMS unit 300, a memory slot unit 400, a slot cover 500, a mesh unit 600and a handle 700.

At least one battery module 100, or a plurality of battery modules 100,may be provided. The following description is based on the case wherethe battery module 100 is provided in plural. The plurality of batterymodules 100 may be stacked along a vertical direction of the batterypack 10 so as to be electrically connected to each other.

Each of the plurality of battery modules 100 may include at least onebattery cell. The at least one battery cell may be a secondary battery,for example a pouch-type secondary battery.

The pack case 200 may package the at least one battery module 100, orthe plurality of battery modules 100 in this embodiment. The pack case200 may include a case base 210, a case body 230 and a case cover 250.

The case base 210 forms a bottom of the pack case 200 and may supportthe plurality of battery modules 100. The case base 210 may include abase mount 212 and a drainage hole 216.

The base mount 212 forms an appearance of the case base 210 and maysupport the plurality of battery modules 100. For this, a battery module100 disposed on the lowermost side among the plurality of batterymodules 100 may be mounted to the base mount 212.

The base mount 212 may have an upper surface that is inclined downwardas being closer to the drainage hole 216, explained later. In otherwords, the upper surface of the base mount 212 may be inclined downwardfrom the center to both ends. Accordingly, even if water or foreignsubstances penetrate into the upper surface of the base mount 212, thepenetrating water or foreign substances may easily flow down to thedrainage hole 216, explained later.

In addition, a channel elongating toward the drainage hole 216,explained later, may be provided at the base mount 212. The channel maybe provided at an upper surface of the base mount 212 to guide smoothmovement of gas such as smoke toward the drainage hole 216, explainedlater.

The channel may be provided in a zigzag form at the upper surface of thebase mount 212 to ensure a longer channel path. If the channel path isensured, when a flame occurs within the battery module 10, it ispossible to effectively prevent or delay the movement of the flametoward the drainage hole 216, explained later, while guiding themovement of the gas along the channel. Accordingly, even though a flameoccurs in the battery module 10, it is possible to effectively preventor delay that the flame is exposed out of the battery module 10 throughthe channel.

Here, the channel may be prepared by forming a plurality of barrierstructures at the upper surface of the base mount 212 or may have agroove structure formed at the upper surface of the base mount 212. Thechannel may have other structure as long as it is able to restrict themovement of the flame while guiding the gas to move toward the drainagehole 216, explained later, from the base mount 212.

The drainage hole 216 communicates with the outside of the pack case 200and may be provided at both sides of the base mount 212. When waterpenetrates into the pack case 200, the drainage hole 216 may dischargethe penetrating water out of the pack case 200.

The drainage hole 216 may be provided below the upper surface of thebase mount 212 to form a step with the base mount 212 as much as apredetermined height h. If water penetrates at the upper side of thepack case 200, the water penetrating at the upper side of the pack case200 may flow down below the pack case 200 along an inner wall of thepack case 200 and then be discharged out of the pack case 200 throughthe drainage hole 216. Here, since the drainage hole 216 is providedbelow the upper surface of the base mount 212, it is possible to preventthe water flowing on the upper inner wall of the pack case 200 frompenetrating into the upper surface of the base mount 212.

The case body 230 forms the most appearance of the pack case 200 and maybe coupled to the case base 210 to accommodate the at least one batterymodule 100, or the plurality of battery modules 100 in this embodiment.

The case body 230 may include a first inner case 232, an outer case 234and a second inner case 236.

The first inner case 232 is to fix the at least one battery module 100,or the plurality of battery modules 100 in this embodiment, and mayinclude four fixing support bars capable of fixing the plurality ofbattery modules 100 at four corners of the plurality of battery modules100 stacked in the vertical direction of the battery pack 10.

The outer case 234 surrounds the first inner case 232 and may form anaccommodation space for accommodating the at least one battery module100, or the plurality of battery modules 100 in this embodiment.

The outer case 234 may have a substantially hexahedral shape to beopened in the vertical direction of the battery pack 10. The outer case234 may be integrally formed by extrusion molding. In other words, theouter case 234 may be formed as a single member to cover all of a frontportion, a rear portion and both side portions of the plurality ofbattery modules 100. The outer case 234 may also be formed as acombination of two members, without being limited to the above.

The outer case 234 may be mounted to the first inner case 232 by slidingalong the vertical direction of the plurality of battery modules 100. Indetail, the outer case 234 may be mounted to the four fixing supportbars of the first inner case 232 by sliding.

In this embodiment, since the outer case 234 is mounted to the firstinner case 232 by sliding as described above, it is possible to omit anadditional bolting member for coupling these members or greatly reducethe number of bolting members.

After being mounted by sliding, the outer case 234 may be sealed withthe case base 210 along an edge thereof by means of a sealant member toensure airtightness with the case base 210. Here, the sealant member maybe made of any material capable of ensuring airtightness, for exampleurethane foam. In other words, the case body 230 and the case base 210may be sealed to each other by means of the sealant member.

The outer case 234 may include a heat-dissipating bead 235.

The heat-dissipating bead 235 is provided at an outer surface of theouter case 234 and may be provided in plural along a length direction ofthe outer case 234. The plurality of heat-dissipating beads 235 mayeffectively dissipate the heat inside the pack case 200 out of the packcase 200 when heat is generated in the pack case 200.

The second inner case 236 is mounted above the outer case 234 and maycover the BMS unit 300, explained later. The second inner case 236 maybe coupled to the case cover 250, explained later.

The second inner case 236 may be sealed with the outer case 234 by meansof the sealant member to ensure airtightness with the outer case 234. Inaddition, the second inner case 236 may be sealed with the case cover250, explained later, by means of the sealant member to ensureairtightness with the case cover 250, explained later.

As described above, in this embodiment, the second inner case 236 andthe outer case 234 may be sealed to each other, the second inner case236 and the case cover 250, explained later, may be sealed to eachother, and the outer case 234 and the case base 210 may be sealed toeach other, respectively. Accordingly, in this embodiment, sealing bythe sealant member is performed on at least three points among the casebase 210, the case body 230 and the case cover 250, explained later, ofthe pack case 200, and thus it is possible to secure more rigidairtightness of the pack case 200.

The case cover 250 forms an upper side of the pack case 200 and may becoupled to the case body 230 to cover the case body 230. The case cover250 may form a space groove S when the case body 230 is coupled thereto.The space groove S is a predetermined space which is exposed only atboth side portions and a rear portion of the battery pack 10, and ahandle 700, explained later, may be provided thereto. This will bedescribed later in more detail in relation to the handle 700.

The BMS unit 300 is provided in the pack case 200 and used forcontrolling the at least one battery module 100, or the plurality ofbattery modules 100 in this embodiment. For this, the BMS unit 300 maybe electrically connected to the plurality of battery modules 100.

The memory slot unit 400 is electrically connected to the BMS unit 300,and a memory unit for firmware update of the BMS unit 300 of the batterypack 10 may be inserted therein. Here, the memory unit is a medium usedfor the firmware update and may be an SD card.

The memory slot unit 400 is disposed between the BMS unit 300 and thepack case 200 inside the pack case 200 and may be partially exposed outof the pack case 200 when the memory unit is inserted.

The slot cover 500 may expose the memory slot unit 400 out of the casecover 250 when the memory unit is inserted by a user or the like. Forthis, the slot cover 500 may be detachably mounted on the case cover250. In detail, the slot cover 500 is provided to be rotatably in ahorizontal direction of the case cover 250 and may be separated from thecase cover 250 or fixed to the case cover 250 according to the rotation.

The mesh unit 600 is used to further ensure waterproofing ordustproofing of the battery pack 10, and at least one mesh pack 600 maybe provided. Hereinafter, the present embodiment will be described basedon the case where the mesh pack 600 is provided in a pair andrespectively mounted to the drainage hole 216, respectively.

The mesh unit 600 may include a first mesh frame 610, a first mesh net630, a second mesh frame 650, a second mesh net 670 and adust-protecting filter 690.

The first mesh frame 610 may be mounted above the drainage hole 216. Thefirst mesh frame 610 may fix the first mesh net 630, explained later, atan upper side of the drainage hole 216.

The first mesh net 630 is mounted to the first mesh frame 610 and may bedisposed above the drainage hole 216. The first mesh net 630 has a netstructure and may prevent foreign substances from penetrating into thepack case 200 from the outside of the pack case 200.

The second mesh frame 650 may be mounted below the drainage hole 216.The second mesh frame 650 may fix the second mesh net 670, explainedlater, at a lower side of the drainage hole 216.

The second mesh net 670 is mounted to the second mesh frame 650 and maybe disposed below the underside of the drainage hole 216 to face thefirst mesh net 630.

The second mesh net 670 has a net structure, similar to the first meshnet 630, and may prevent foreign substances from penetrating into thepack case 200 from the outside of the pack case 200. As described above,in this embodiment, the mesh unit 600 may more reliably prevent foreignsubstances or the like from penetrating into the pack case 200 by meansof a double net structure of the first mesh net 630 and the second meshnet 670.

The second mesh net 670 and the first mesh net 630 may be arranged withmutually alternating net structures for more reliable waterproofing ordustproofing. In other words, the net shape of the first mesh net 630may be interlaced with the net shape of the second mesh net 670 in thevertical direction of the battery pack 10.

In addition, it is also possible that a plurality of mesh nets areprovided, more than one pair. If the plurality of mesh nets areprovided, namely if three or more mesh nets are provided, the pluralityof mesh nets may be stacked in order from top to bottom. Here, the meshnets facing each other in the vertical direction may be arranged suchthat the net shapes are mutually alternating in the vertical direction,similar to the first and second mesh nets 630, 670.

The first and second mesh nets 630, 670 will be described in detailagain.

Detailed specifications of the first mesh net 630 and the second meshnet 670 are shown in Table 1 below.

TABLE 1 spacing be- kind of wire unit net pore tween first mesh netdiameter of diameter of poros- and second (Plain mesh net mesh net itymesh nets flame Weave) (mm) (mm) (%) (mm) passing 20 0.457 0.81 41 1 O 2or above X 30 0.355 0.49 33.5 1 O 2 or above X

As shown in Table 1, the mesh nets (the first mesh net 630 and thesecond mesh net 670) may be made of Plain Weave 20 or 30.

First, if the mesh nets (the first mesh net 630 and the second mesh net670) are made of Plain Weave 20, wires of the net structure may have adiameter of 0.457 mm and a unit net pore of the net structure may have adiameter of 0.81 mm. Also, the overall net structure may have porosityof 41%.

And, if the mesh nets (the first mesh net 630 and the second mesh net670) are made of Plain Weave 30, wires of the net structure may have adiameter of 0.355 mm, and a unit net pore of the net structure may havea diameter of 0.49 mm. Also, the overall net structure may have porosityof 33.5%.

In both cases of Plain Weave 20 and the Plain Weave 30, if a spacingbetween the first mesh net 630 and the second mesh net 670 is 2 mm orabove, the flame may not pass out of the pack case 200. If fire occursinside the pack case 200 of the battery pack 10 due to a short circuitor the like, flame and smoke may be generated inside the pack case 200.At this time, if the flame passes through the mesh unit 600 directly outof the pack case 200 in addition to the smoke, the fire may be rapidlyspread due to the flame passing out of the pack case 200. Thus, thefirst mesh net 630 and the second mesh net 670 may disposed to be spacedapart from each other by at least 2 mm in order to so as to prevent theflame from passing.

The dust-protecting filter 690 is used to filter the foreign substancesor the like and may be provided between the first mesh net 630 and thesecond mesh net 670. The dust-protecting filter 690 may employ a filtercapable of filtering foreign substances such as dust of at least 10 μm.

The dust-protecting filter 690 may have a volume corresponding to thespace between the first mesh net 630 and the second mesh net 670. Inother words, the dust-protecting filter 690 may be sized to completelyfill the space between the first mesh net 630 and the second mesh net670. This is to more reliably prevent the foreign substances such asdust from passing through the space between the first mesh net 630 andthe second mesh net 670.

The handle 700 is used to guide the delivery of the battery pack 10 bythe user during the transportation of the battery pack 10 and may beprovided at both side surfaces of the case cover 250.

The handle 700 may form a space groove S when the case body 230 and thecase cover 250 are coupled. Seeing the structure of the handle 700 inmore detail, one end of the handle 700 may be spaced a predetermineddistance from the front surface of the case cover 250 to the rear of thecase cover 250, and the other end of the handle 700 may be disposed atthe rear surface of the case cover 250.

The handle 700 may be formed integrally with the case cover 250.Accordingly, in this embodiment, the handle 700 is integrally formed atthe case cover 250, instead of being separately attached to the packcase 200, and thus it is possible to reduce cost and time formanufacturing the handle.

Hereinafter, the transportation of the battery pack 10 by using thehandle 700 will be described in more detail.

FIGS. 9 and 10 are diagrams for illustrating how to transport thebattery pack of FIG. 1.

Referring to FIGS. 9 and 10, first, the handle 700 of the battery pack10 is disposed in the space groove S and exposed only at both sideportions and a rear portion of the battery pack 10, so that the handle700 may not be exposed to the user at the front portion of the batterypack 700. In other words, the front portion of the battery pack 10 doesnot protrude, and thus the beauty of the battery pack 10 may not bedeteriorated in an aesthetic point of view.

When the user or the like wants to move the battery pack 10, the usermay put the hands into the space grooves S provided at both sides of thepack case 200, grab the handle 700 and then move the battery pack 10.Since the user or the like may transport the battery pack 10 by holdingthe handles 700 provided at both sides of the pack case 700, the batterypack 10 may be transported more reliably.

FIGS. 11 to 13 are diagrams for illustrating how to mount a mountbracket of the battery pack of FIG. 1.

Referring to FIGS. 11 to 13, the battery pack 10 may further include amount bracket 800.

The mount bracket 800 is detachably mounted to the pack case 200 and mayallow the battery pack 10 to be mounted to an exterior structure W. Theexterior structure W may be, for example, a wall of a house. In otherwords, the mount bracket 800 may guide the battery pack 10 to be fixedin a wall-hanging manner.

The mount bracket 800 may include a pack mounting portion 810 and astructure mounting portion 830.

The pack mounting portion 810 is mounted to the pack case 200 by using ascrew member or the like and may be disposed within the space groove S.The structure mounting portion 830 is bent from the pack mountingportion 810 and may be mounted to the exterior structure W by using thescrew member or the like.

Meanwhile, the pack mounting portion 810 and the structure mountingportion 830 may be disposed within the space groove S. In other words,the mount bracket 800 may be disposed within the space groove S whenmounted to the pack case 200. Accordingly, when being mounted to thepack case 10 and the exterior structure W, the mount bracket 800 may behidden by the front surface of the case cover 250 in front of thebattery pack 10. Thus, when the battery pack 10 is mounted in awall-hanging manner, the mount bracket 800 is not observed in front ofthe battery pack 10 and thus may not hinder the aesthetic sense in termsof design.

As described above, the battery pack 10 of this embodiment may have amore airtight and efficient waterproofing and dustproofing structure bymeans of the above-mentioned structure. In addition, the battery pack 10of this embodiment may be easily transported and installed by means ofthe above-mentioned structure and may secure an aesthetic sense in termsof design.

While the embodiments of the present disclosure have been shown anddescribed, it should be understood that the present disclosure is notlimited to the specific embodiments described, and that various changesand modifications can be made within the scope of the present disclosureby those skilled in the art, and these modifications should not beunderstood individually from the technical ideas and views of thepresent disclosure.

What is claimed is:
 1. A battery pack, which includes at least onebattery module and a pack case for packaging the at least one batterymodule, the battery pack comprising: a case base configured to supportthe at least one battery module; a case body coupled to the case base toaccommodate the at least one battery module; and a case cover coupled tothe case body to cover the case body, wherein the case base and the casebody are sealed to each other and the case body and the case cover aresealed to each other, respectively, by means of a sealant member along arim thereof.
 2. The battery pack according to claim 1, wherein the casebody includes: a first inner case configured to fix the at least onebattery module; an outer case configured to surround the first innercase and form an accommodation space for accommodating the at least onebattery module; and a second inner case mounted to an upper side of theouter case and coupled to the case cover.
 3. The battery pack accordingto claim 2, wherein the second inner case is mutually sealed to theouter case by means of the sealant member.
 4. The battery pack accordingto claim 2, wherein the second inner case is mutually sealed to the casecover by means of the sealant member.
 5. The battery pack according toclaim 2, wherein the outer case is mutually sealed to the case base bymeans of the sealant member.
 6. The battery pack according to claim 1,wherein the case base includes: a base mount mounted to the at least onebattery module; and drainage holes provided at both sides of the basemount and formed to have a step from the base mount.
 7. The battery packaccording to claim 6, wherein an upper surface of the base mount isinclined downwards toward the drainage hole.
 8. The battery packaccording to claim 6, further comprising: at least one mesh unit mountedto the drainage hole.
 9. The battery pack according to claim 8, whereinthe at least one mesh unit includes: a first mesh frame mounted to anupper side of the drainage hole; a first mesh net mounted to the firstmesh frame; a second mesh frame mounted to a lower side of the drainagehole; and a second mesh net mounted to the second mesh frame anddisposed opposite to the first mesh net.
 10. The battery pack accordingto claim 9, wherein the first mesh net and the second mesh net arearranged with mutually alternating net structures.
 11. The battery packaccording to claim 9, wherein the first mesh net and the second mesh netare spaced apparat from each other by at least 2 mm.
 12. The batterypack according to claim 9, wherein the at least one mesh unit includes adust-protecting filter provided between the first mesh net and thesecond mesh net.
 13. The battery pack according to claim 12, wherein thedust-protecting filter has a volume corresponding to the space betweenthe first mesh net and the second mesh net.
 14. The battery packaccording to claim 13, wherein the dust-protecting filter filters offforeign matter including dust with a size of 10 μm or above.
 15. Thebattery pack according to claim 1, wherein the battery pack is a homeenergy storage device.